Dissolved palladium in heavy traffic location runoff: dynamic variation and influencing factors

Abstract

ABSTRACTPalladium (Pd) is widely used in vehicle exhaust catalysts (VECs) and rapidly increasing in urban environments worldwide. This research collected runoff samples in a typical heavy traffic location and analysed the concentrations of dissolved palladium by inductively coupled plasma-mass spectrometry (ICP-MS). For most precipitation events, the maximum Pd concentration level occurred at the beginning of the runoff period and then decreased in subsequent runoff. The results showed that the Pd concentration in runoff was lower in the wet season when compared with the dry season. The wet season had fewer clear days to accumulate pollutants on the impervious surface and had a higher precipitation intensity to dilute dissolved Pd in runoff. Our experimental results also proved that the migration and transformation of palladium in urban environments are affected by runoff water quality parameters. Lower pH, higher Eh and higher concentrations led to a higher dissolved Pd concentration.